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Excision of lipomatous hypertrophy of the interatrial septum via port-access

Department of Cardiovascular and Thoracic Surgery, OLV Clinic, Aalst, Belgium

Received 28 October 2007; received in revised form 20 January 2008; accepted 22 January 2008

Dr Vanermen discloses a financial relationship with Cardiovations.

*Corresponding author. Florence Nightingale Hastanesi No: 290, 80220 Sisli, Istanbul, Turkey. Tel.: +90 2122244950/4173; fax: +90 2122258396.

E-mail address: Caynakbaris{at}hotmail.com (B. Caynak).

	Abstract

Top Abstract 1. Introduction 2. Discussion References

 
We present the surgical resection and repair, using port-access, in a case of extensive lipomatous hypertrophy of the interatrial septum (IAS). There was tumourous lipomatous hypertrophy on the superior vena cava (SVC) – atrial junction close to the aortic root beside massive IAS hypertrophy. Resection of involved IAS and SVC was performed using bovine pericardium for the repair.

Key Words: Minimally invasive surgery; Tumour; Port-access

	1. Introduction

Top Abstract 1. Introduction 2. Discussion References

 
Lipomatous hypertrophy of the IAS (LHIAS) is a rare tumour although morphologically and pathologically well described. It is usually diagnosed incidentally and its clinical course is poorly understood as most data are derived from post-mortem studies [1]. Lipomatous hypertrophy of the right atrium is typically limited to the interatrial septum, extensive lipomatous hypertrophy which protrude into the other portions of the right atrium being extremely rare [2].

The patient was a 61-year-old male. Ten months prior to this presentation, an incidental finding on CT was made of an asymptomatic right atrial tumour causing some compression of the superior vena cava. Over the following months, he noticed a deteriorating exercise tolerance with exertional dyspnoea. Chest X-ray and ECG were unremarkable. Transoesophageal echo demonstrated tumourous hypertrophy of the atrial septum with a 4x3.3 cm mass extending into the right atrium, compression of the superior vena cava and a patent foramen ovale. Coronary angiography was unremarkable. His latest CT showed lipomatosis of the interatrial septum and of the right atrioventricular groove (Fig. 1).

View larger version (75K): [in this window] [in a new window]   Fig. 1. Preoperative CT-scan image of lipomatous hypertrophy of interatrial septum. (Arrowhead shows the lesion.)

The patient underwent port-access excision of lipomatous hypertrophy of interatrial septum and bovine pericardial patch plasty.

The surgical technique of port-access has been extensively reported elsewhere [3]. The procedure is performed through a 4-cm working port located in the right inframammary groove, usually in the fourth intercostal space. Dedicated, long instruments are a prerequisite with this technique. Visualisation is accomplished with an endoscope through a separate port in the fourth intercostal space at the anterior axillary line. Another port is used for suction and carbon dioxide insufflation. A left atrial retractor is introduced through a stab wound in the fourth intercostal space, just lateral to the right internal mammary artery. Femoro-femoral extracorporeal circulation (ECC) is used as well as an endoaortic balloon, to occlude the aorta, and antegrade cold crystalloid cardioplegia. The whole procedure is performed using a double-lumen endotracheal tube and transoesophageal echocardiographic guidance.

The pericardium was entered after commencing ECC. An abnormal bulging of epicardial fat was noted at the site of the interatrial groove. On exposing the groove we found a distinct tumour of 2x2 cm in size (Fig. 2). Further extracardiac dissection at the interatrial groove was performed prior to clamping the SVC and incising the right atrium. The first tumour, which extended up to the SVC and with its upper pole adjacent to the aorta, was removed en-bloc, closing the defect with 4.0 prolene. The remaining tumour was seen to extend from the fossa ovalis to the origin of the SVC. We clamped the aorta with the endoaortic balloon and arrested the heart by antegrade cold crystalloid cardioplegia. The interatrial septum was opened at the fossa ovalis allowing extensive resection of the hypertrophied septum. We repaired the defect with the bovine pericardial patch measuring 5x3 cm with continuous prolene 4-0. The endoaortic balloon was deflated and the right atrium was closed. The patient was weaned, without support, from ECC using AV sequential pace rhythm.

View larger version (113K): [in this window] [in a new window]   Fig. 2. Operative field view of the distinct tumour.

Following surgery he had an unremarkable initial recovery and was in normal sinus rhythm on the first postoperative day. On the 3rd postoperative day he developed abdominal distension requiring an exploratory laparotomy with small bowel decompression. Following the laparotomy, he remained haemodynamically stable. Respiratory wean was, however, delayed due to abdominal pain and prolonged intubation, with eventual extubation seven days after the laparotomy. Transthoracic echocardiogram showed no residual SVC obstruction and an intact interatrial septum with patch. The patient was discharged home on the 30th postoperative day.

	2. Discussion

Top Abstract 1. Introduction 2. Discussion References

 
Lipomatous hypertrophy is a non-encapsulated benign hypertrophic alteration of the normal tissues of the interatrial septum. It is a rare tumour with few cases of surgical excision reported in the literature [2, 4] or echocardiographically described [5].

Macroscopically it cannot be differentiated from epicardial fat. Histologically, it is characterised by mostly adult adipocytes interspersed with hypertrophic cardiac muscle fibres [6]. Supraventricular arrhythmias are significantly increased in clinically, and occasionally haemodynamically, significant obstruction of the atrial inflow or outflow tract is observed. In this case, TEE examination and in particular intraoperative findings revealed a dramatic obstruction at the SVC-atrial junction causing a reduction in exercise tolerance with exertional dyspnoea.

TTE, TEE, computed tomography and magnetic resonance imaging are useful investigations for diagnosis and in planning surgery [2, 4]. Endomyocardial biopsy may be performed for differential diagnosis. TEE findings in this case of a mass in the interatrial septum and the separate mass in the SVC-atrial junction both showing highly echogenic structures, is consistent with a diagnosis of lipomatous hypertrophy.

Indications for surgical resection of LHIAS include SVC obstruction or intractable rhythm disturbances [7, 8]. In most cases there is no need for complete excision. If complete excision is planned, reconstruction of the interatrial septum using a pericardial or Dacron patch should be performed [8].

Right and left atrial procedures are routinely performed in our unit using port-access. We also believe that, due to the poor clinical condition of our patient, this minimal access approach might confer an additional advantage. Complete excision of the tumuoral mass on the SVC-atrial junction and extensive excision of the IAS with bovine pericardial patch plasty was performed.

	References

Top Abstract 1. Introduction 2. Discussion References

 

1. Fletcher CDM. Diagnostic histopathology of tumors, 1. New York: Churchill Livingstone; 1995:22–25.
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4. Breuer M, Wippermann J, Franke U, Wahlers T. Lipomatous hypertrophy of the interatrial septum and upper right atrial inflow obstruction. Eur J Cardiothorac Surg 2002;22:1023–1025.[Abstract/Free Full Text]
5. Reyes CV, Jablokow VR. Lipomatous hypertrophy of the cardiac interatrial septum. A report of 38 cases and review of the literature. Am J Clin Pathol 1979;72:785–788.[Medline]
6. Burke AP, Litovsky S, Virmani R. Lipomatous hypertrophy of the atrial septum presenting as a right atrial mass. Am J Surg Pathol 1996;20:678–685.[CrossRef][Medline]
7. Kucukarslan N, Kirilmaz A, Ulusoy E, Baysan O, Yildirim V, Ozal E, Sahin MA, Tatar H. Eleven-year experience in diagnosis and surgical theraphy of right atrial masses. J Card Surg 2007;22:39–42.[CrossRef][Medline]
8. Zeebregts CJ, Hensens AG, Timmermans J, Pruszczynski MS, Lacquet LK. Lipomatous hypertrophy of the interatrial septum: indications for surgery. Eur J Cardiothorac Surg 1997;11:785–787.[Abstract]

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This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Personal Folders Download to citation manager Author home page(s): Baris Caynak Frank Van Praet Nicholas Walcot Hugo Vanermen Permission Requests Citing Articles Citing Articles via HighWire Google Scholar Articles by Caynak, B. Articles by Vanermen, H. PubMed PubMed Citation Articles by Caynak, B. Articles by Vanermen, H. Related Collections Cardiac - other Minimally invasive surgery Related Article